JP2006111314A - Paper container - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a paper container capable of easily forming an opening part by a method different from a method for coating an anti-heat seal agent on a surface of thermoplastic resin of an innermost layer of a laminate used for a gable-top type paper container. <P>SOLUTION: In the paper container, a gable-type roof part is formed by folding roof part folding side panels 1G, 3G continuous to and facing an upper side of a square prismatic barrel portion consisting of four side panels inwardly at each obliquely folding line by using a laminate the base material of which is a cardboard overlaid with thermoplastic resin as the innermost layer, and folding remaining roof panels 2G, 4G facing each other inwardly. An overlapping part to hold folding ribs continuously provided on the upper sides of the roof part folding side panels 1G, 3G by ribs continuously provided on the upper sides of the roof panels 2G, 4G is formed by heat-sealing. In this situation, an electron beam irradiation pattern is formed by irradiating at least a part of the surface of the thermoplastic resin of the innermost layer of the overlapping part with electron beam. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

  The present invention relates to a technique for imparting easy-openability to a gobeltop paper container such as milk and fruit juice drink.

In gobel top paper containers (gable roof paper containers) that have become established as paper containers for liquids such as milk, fruit juice drinks, dairy drinks, mineral water, etc., an anti-heat sealant is partially applied to the inner surface of the rib (top panel) A technique for forming an opening that is easy to open from a part by coating and partially weakening the heat seal strength between the ribs (see, for example, Patent Document 1). In addition, a method has been proposed in which a plastic spout prepared separately from the paper container is stuck and fixed to the roof portion from the outside, and the liquid inside is poured out from the spout. In addition, a plastic spout tool with a cap is attached to the roof with a heat seal, and the spout tool is a one-piece plastic molded product. An economy type in which a product is destroyed and a spout is opened has been proposed (see, for example, Patent Document 2).
Japanese Utility Model Publication No. 9-191 Japanese Utility Model Publication No.3-1380

  However, when an anti-heat sealant layer is provided on the back surface of the rib portion, it takes time and labor to dry the anti-heat seal agent in the process of partially coating the anti-heat seal agent at a predetermined position of the rib on the inner surface of the carton. There is a risk that the coating amount is likely to vary and there is a risk of lack of stability. In this case, there is a problem of causing unsuccessful opening.

  In addition, the method of piercing the spout prepared separately from the carton from the outside reduces the total cost if the spout is used repeatedly, but there is the inconvenience that the spout must be present at the time of use of the product in the paper container, If the same spout is used as it is in another paper container with different contents, there is a problem that the contents are mixed, and repeated use without washing also has a hygienic problem.

  In addition, attaching plastic spouts to the roof of individual gable-top cartons has the problem of leading to increased costs even if they are of the economy type. There is also the problem of making it difficult.

  Today, according to the requirements of the retail industry, there is a tendency to increase the pressure at the time of heat sealing in the molding and filling machine in order to reduce liquid leakage at the distribution stage of the paper container. It is becoming difficult to open. On the other hand, end users are increasingly demanding clean and easy-to-open paper containers. The industry has such a trade-off problem.

  The present invention has been made in view of such a problem, and is different from a method of applying an anti-heat sealant to the innermost thermoplastic resin surface of a laminate used for a paper-belt type paper container. An object of the present invention is to provide a paper container in which an opening can be easily formed.

  In order to solve the above-mentioned problems, the present invention uses a laminate in which a thermoplastic resin is laminated on the innermost layer using paperboard as a base material, and a fold line is formed on the upper side of a quadrangular columnar body made of four side panels. Folding panels on the opposite side of the roof part that are connected via the inner side are folded inward by oblique fold lines, and the remaining opposite roof panels are folded inward to form a gable-shaped roof part that is connected to the upper side of the roof panel. In a paper container formed by heat-sealing the overlapped portion so as to sandwich the folded rib continuously provided on the upper side of the roof portion folding side panel by the provided rib, the innermost layer of the thermoplastic resin of the overlapped portion An electron beam irradiation pattern is formed on at least a part of the surface by electron beam irradiation. Further, the electron beam irradiation pattern is formed by electron beam irradiation in a predetermined pattern on both the inner surface of the folding rib on the opening side and the rib facing the inner surface, or on either inner surface thereof. is there.

  According to the present invention, the innermost thermoplastic resin layer of the laminate that is the base material of the paperbelt type paper container is partially processed, that is, the roof part folding side panel is provided by the rib continuously provided on the upper side of the roof panel. By forming an electron beam irradiation pattern by electron beam irradiation on at least a part of the surface of the thermoplastic resin of the innermost layer of the overlapping portion formed so as to sandwich the folding rib continuously provided on the upper side, easily, The spout can be opened cleanly, uniform processing can be performed as compared with the conventional anti-heat sealant method, stable opening is possible, and anxiety of liquid leakage can be prevented.

  Hereinafter, the paper container of this invention is demonstrated in detail using drawing. FIG. 1 is a perspective view showing the external shape of a paper container A according to the present invention, and FIG. 2 is a development view of a blank 10 before assembling the paper container A of the present invention. As shown in FIG. 2, the body portion D of the blank 10 of the paper container A according to the present invention has the side panels 1 to 4 and the adhesive margin piece 5 connected continuously via the polygonal lines a, b, c and d, and on the upper side thereof. The roof part 2G, 4G and the roof panel folding side panels 1G, 3G corresponding to the gables (mountain wall portions at both ends of the gable roof) are broken lines e. The ribs T and the ribs 2T and 4T which wrap around the ribs 2T and 4T and enclose and seal them as rib portions T are connected to each other via a broken line f. In addition, oblique folding lines h and h and folding lines j and j that are obliquely folded are provided in the roof folding side panels 1G and 3G, respectively. After filling the paper container A with the contents, top sealing is performed by heat sealing between the ribs. The bottom portion B is composed of a portion connected to the lower side of the body portion D via a broken line g, and these are heat-sealed to form a flat bottom portion without liquid leakage.

  The laminate structure of the laminate used in the paper container A of the present invention is preferably one in which both surfaces of a conventionally used paperboard layer are coated with a polyolefin resin. As the polyolefin resin, low density polyethylene, linear Low density polyethylene, medium density polyethylene, polypropylene, ionomer, ethylene / vinyl acetate copolymer, ethylene / acrylic acid copolymer, ethylene / acrylic acid ester, ethylene / vinyl alcohol copolymer, etc. may be selected. Further, instead of the paperboard alone, a laminate of paper / polyethylene / aluminum foil, paper / ethylene / acrylic acid copolymer / aluminum foil, paper / polyethylene / aluminum foil / biaxially stretched polyester, or the like may be used.

  In order to form the paper container A of the present invention from the blank 10 produced by processing the above laminated body, first, the blank 10 is vertically folded in three along the fold line c (right) and the fold line a, and the adhesive margin piece 5 and the side. The panel 1, the roof folding side panel 1G, and the folding rib 1T are heat-sealed and affixed to a cylinder to obtain a flat folded state. The folded paper container is supplied to a molding and filling machine, raised in a prismatic shape, first molded at the bottom, filled with contents, then molded into a gable roof, and finally the rib portion T is heat sealed. Seal. In this top seal, when the roof folding side panels 1G and 3G are first folded inward by the oblique folding lines h and h, the folding lines j and j, and the folding line e, the folding ribs 1T and 3T on the top are folded in the center. The two ribs 2T and 4T are folded inward at k and l, and the remaining ribs 2T and 4T are also collapsed inward at the same time. Completed and finished in a gable-top paper container A. In this case, the four ribs to be polymerized are thermally welded by the thermoplastic resin layer.

  FIG. 3 is an explanatory view of opening a gable top type paper container. FIG. 3A is a perspective view showing a state before opening. When the roof panel 2G and the roof panel 4G that overlap the roof folding side panel 3G on the paper container opening side are strongly opened left and right with both hands, the folding ribs 3T, ribs 2T, and 4T that are quadruple heat-sealed are the folding ribs 3T. And the rib portion becomes T-shaped as shown in FIG. When the left and right sides are pressed with fingers as shown by the arrows and pulled forward, the peeling starts from the point where the five folding lines of the folding rib 3T intersect, and the peeling spreads to the left and right and finally, as shown in FIG. Thus, the spout M can be opened.

  A little force is required until the T-shaped half-opened state shown in FIG. 3B, but anyone can easily open it. From this state, as shown in FIG. 3C, how to open easily is the subject of the present invention, and the means will be described below, but before that, the conventional anti-heat sealant method is described. deep. A conventional anti-heat sealant is partially coated on the inner surface of a blank of a paper container at three locations in the pattern shown in FIG. The folding rib 3T is folded at the center and is thermocompression bonded by the inner surfaces of the opposing ribs 2T and 4T. Therefore, the peel strength at this portion is small, and it peels easily at the interface of the anti-heat sealant layer. Moreover, as shown to FIG. 4-a and b, even if it is the pattern which partially coated the anti-heat seal agent on the single side | surface heat-sealed, the peeling strength of this part can be made small.

  The point in the present invention is that an electron beam irradiation pattern P is formed by electron beam irradiation at predetermined positions as shown in FIG. 4 on the inner surfaces of the folding ribs 1T, ribs 2T, and folding ribs 3T instead of the anti-heat sealant. It is. As shown in FIGS. 4A and 4B, the electron beam irradiation pattern P is provided with an electron beam irradiation pattern P having a predetermined shape on one of the opposing rib inner surfaces, or as shown in FIG. In addition, it may be provided on both opposing surfaces. The shape of the electron beam irradiation pattern P is not necessarily limited to a rectangle as shown in FIG. Moreover, as shown to FIG. 4-d, it is good also as a shape containing the broken line e.

  By applying the electron beam irradiation as described above to the folding ribs 1T, 2T, and folding ribs 3T, the opposing folding ribs 2T and ribs 4T and folding ribs are provided in the same manner as when the conventional anti-heat sealant is applied. The heat seal strength between 3T and the ribs 2T, 4T can be weakened, an excellent easy-opening property can be obtained, and an effect of easily forming the spout M can be produced.

  Next, a method for forming the electron beam irradiation pattern P will be described. The processing of the electron beam irradiation pattern P can be performed simultaneously or continuously in a process for producing a known paper container. That is, using a known electron beam irradiation apparatus or the like, an electron beam irradiation pattern P is formed by partially irradiating a predetermined position of the blank with an electron beam in a range of 25 to 500 kGy. The polyolefin resin layer of the electron beam irradiation pattern P irradiated with this electron beam is cross-linked, and is difficult to melt and adhere even when hot air is applied, and can be peeled off after heat sealing.

  In the above, if the electron beam irradiation dose is less than 25 kGy, the adhesiveness in heat sealing cannot be weakened and peeling becomes impossible. On the other hand, if the electron beam irradiation dose exceeds 500 kGy, it is generated as a decomposition product. For example, it is not preferable because odor or the like due to carboxylic acid or the like is generated. In addition, it is necessary to set the conditions of electron beam irradiation suitably according to the kind of resin used for the innermost layer of a laminated body, thickness, etc.

  In order to partially irradiate the electron beam, paper is supplied intermittently to a fixed metal shielding plate, or an irradiation device is installed in a cylinder on a metal cylinder and the cylinder is rotated to supply paper. It is also possible to irradiate continuously.

The liquid paper container according to the present invention was applied to milk to prepare a carton blank having an internal volume of 1000 ml. As the carton base material, the one having the following laminated structure manufactured by Weerhauser, which is currently used for milk, was used as it was. That is, in order from the surface, it has a layer structure of polyethylene 16 g / m ² / bleached kraft paper 313 g / m ² / polyethylene 27 g / m ² , and the total basis weight is 356 g / m ² . In order to form the electron beam irradiation pattern P as shown in FIG. 4-c on the back surface of the folding rib 1T of the carton blank made of this laminated material, an electron beam irradiation device (CB250 / 30/20 mA, manufactured by Iwasaki Electric Co., Ltd.) is used. It was used and irradiated with an electron beam of 300 kGy under the condition of a conveyance speed of 8 m / min. This electron beam was partially irradiated. The blank 10 according to the present invention obtained by performing such processing was cylinder-attached with the same frame sealer as before, and then molded, filled and sealed under the same conditions by a milk molding and filling machine. Twenty samples were randomly extracted from the product thus obtained, and the opening test was conducted with five panelists. As a result, there was a sense of incongruity with a product using a conventional anti-heat sealant. It turns out that it opens easily. Furthermore, the push-pull scale (manufactured by Imada Seisakusho Co., Ltd.) was tested for the peel resistance value at the time of opening by adding a comparative example sample in which no processing was performed on the rib portion, and the following results were obtained.
Carton with anti heat sealant 1.4 Kg
Carton by electron beam irradiation (present invention) 1.3 Kg
Comparative example (carton without processing) 3.0 Kg
As can be seen from the above results, the liquid paper container according to the present invention has an easy-opening property comparable to the case of using the anti-heat sealant. Depending on the position of the other electron beam irradiation pattern P shown in FIG. 4, the initial resistance value and the resistance value in the middle may be slightly different, but it can be opened with almost the same force.

  The paper container by this invention is not limited to the Example mentioned above, A various deformation | transformation is possible within the range which does not deviate from the summary of this invention. For example, the blank of the gobeltop type paper container of the present embodiment is drawn in a pure pack type, but is also effective for other types of gobeltop type paper containers. The horizontal cross section of the paper container according to the present invention is square, but may be rectangular.

  INDUSTRIAL APPLICABILITY The present invention can be widely used for gobeltop-type paper containers such as milk and fruit juice drinks, and in particular, can be widely used for gobeltop-type paper containers that impart easy-openability.

It is a perspective view which shows the external appearance shape of the paper container of this invention. It is an expanded view which shows the blank of the paper container of this invention. It is a perspective view explaining the procedure which opens the paper container of this invention and forms a spout. It is explanatory drawing which shows the electron beam irradiation pattern in the blank of the paper container of this invention.

Explanation of symbols

A Paper container D Body part 1-4 Side panel 5 Glue piece G Roof part 1G Roof part folding side panel 2G Roof panel 3G Roof part folding side panel 4G Roof panel T Rib part 1T Folding rib (top panel)
2T rib (top panel)
3T Folding rib (top panel)
4T rib (top panel)
a to i broken line h to j oblique broken line k, l broken line 10 blank M opening P electron beam irradiation pattern

Claims (2)

Using a laminate in which a thermoplastic resin is laminated on the innermost layer using paperboard as a base material, facing roof part folding side panels arranged continuously on the upper side of a quadrangular columnar body consisting of four side panels via a broken line Are folded inward by diagonal fold lines, the remaining facing roof panels are folded inward to form a gable-shaped roof, and the ribs connected to the upper side of the roof panel are connected to the upper side of the roof part folding side panel. In a paper container formed by heat-sealing the overlapped part so as to sandwich the continuous folding rib,
A paper container, wherein an electron beam irradiation pattern is formed by electron beam irradiation on at least a part of the surface of the thermoplastic resin of the innermost layer of the overlapping portion. 2. An electron beam irradiation pattern is formed by electron beam irradiation in a predetermined pattern on both or one of the inner surfaces of the folding ribs on the opening side and the ribs facing each other. The paper container described.

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